@article{duarte_yadav_castorena_2024, title={Using Color Measurements to Quantify Aggregate and Asphalt Emulsion Compatibility}, volume={5}, ISSN={0361-1981 2169-4052}, url={http://dx.doi.org/10.1177/03611981241242754}, DOI={10.1177/03611981241242754}, abstractNote={The compatibility of asphalt emulsion and aggregate plays a significant role in the aggregate retention performance of chip seals. There are several, similar standardized test methods available for assessing the compatibility of emulsion–aggregate blends, including AASHTO T 59, ASTM D244, and North Carolina Department of Transportation (NCDOT) A-24. In all methods, a sample of aggregate and emulsion is mixed and rinsed. Subsequently, the compatibility of the rinsed sample is reported as “good,”“fair,” or “poor” based on visual inspection of asphalt coating the aggregate surface area. These visual inferences are subjective, making them susceptible to potential operator bias. The aim of this study is to develop an objective means to quantify emulsion–aggregate compatibility by using the Asphalt Compatibility Tester to obtain color-based measures in lieu of the visual assessment procedures. Multiple aggregate sources (granite, limestone, and lightweight), emulsion types (CRS-2L, CRS-2, and SS-1h), and sources were evaluated. In total, 25 emulsion–aggregate blends were analyzed. The results were used to establish color index thresholds to capture good- versus fair- or poor-performance emulsions. Additionally, chip seal samples from five construction projects were subjected to the Vialit test to measure aggregate retention performance. The Vialit test results were compared with the compatibility test results as a preliminary evaluation of the color-based criteria proposed here. The results indicated that the NCDOT A-24 procedure coupled with color measurements is effective at capturing the compatibility of emulsion–aggregate blends, providing a potential means to remove the subjectivity of the current visual rating procedures.}, journal={Transportation Research Record: Journal of the Transportation Research Board}, publisher={SAGE Publications}, author={Duarte, Gabriel Macedo and Yadav, Shivpal and Castorena, Cassie}, year={2024}, month={May} }
 @article{yadav_kusam_tayebali_2021, title={Evaluating Moisture Damage Using Impact Resonance Test}, volume={49}, ISSN={["1945-7553"]}, DOI={10.1520/JTE20200372}, abstractNote={Abstract
               Moisture damage in asphalt mixtures has been a major cause for premature failure of asphalt pavements for decades. Although a lot of research has been done and many test methods have been developed to evaluate moisture damage in asphalt mixtures, not much research has been done on the use of nondestructive testing techniques to evaluate moisture damage in asphalt mixtures. The impact resonance (IR) test is a nondestructive test that is used to determine material properties like dynamic elastic modulus. The IR test on asphalt mixtures is done on a thin-disk specimen (150-mm diameter and 25-mm thickness). In this study, the IR test was used to assess moisture damage in asphalt mixtures by determining the resonant frequency of asphalt mixture samples in the unconditioned and moisture conditioned state. The relative reduction (ER) in dynamic elastic modulus was calculated as the ratio of the resonant frequency of conditioned and unconditioned specimens from the IR test, which was used to evaluate moisture damage. Moisture sensitivity of the asphalt mixtures was also determined by the tensile strength ratio (TSR) test. Two different moisture conditioning procedures were used for both the IR test and TSR test—modified AASHTO T 283 (Standard Method of Test for Resistance of Compacted Asphalt Mixtures to Moisture-Induced Damage) and Moisture Induced Stress Tester (MIST) conditioning. Six different mixtures from three different aggregate sources were used in this study. A good correlation was observed between TSR values from the TSR test using both conditioning procedures and the ER values from the IR test using both conditioning procedures for the asphalt mixtures used in this study. This study shows that the IR test can be used to evaluate moisture damage in asphalt mixtures. This study also explored the effects of various parameters such as support condition, impact source, and impact location on the resonant frequency from the IR test.}, number={6}, journal={JOURNAL OF TESTING AND EVALUATION}, author={Yadav, Shivpal and Kusam, Abhilash and Tayebali, Akhtarhusein A.}, year={2021}, month={Nov}, pages={4118–4134} }
 @article{rashetnia_kusam_yadav_pour-ghaz_tayebali_2022, title={Quantifying moisture damage in asphalt concrete using axisymmetric flexural vibration technique}, volume={23}, ISSN={["1477-268X"]}, DOI={10.1080/10298436.2020.1757671}, abstractNote={ABSTRACT The Tensile Strength Ratio (TSR) test is commonly used to quantify the moisture susceptibility of asphalt mixtures. This test method is based on the indirect tensile strength, which is not a fundamental property and hence cannot be used in the asphalt mixture design process. Therefore, alternative test methods that use a fundamental property to quantify moisture sensitivity of asphalt mixtures are needed. This study investigates if the linear impact resonance shift and frequency spectrum bandwidth changes measured using Axisymmetric Flexural Vibration (AFV) technique can be used to quantify moisture damage. This test enables calculation of the dynamic elastic modulus of the disk, based on measured resonance frequency as well as quantification of vibration energy dissipation in the specimens based on the change in bandwidth of frequency spectrum. AFV test is used to quantify moisture damage susceptibility of asphalt mixture specimens with different moisture conditioning levels and different mixture designs. The results of the AFV test are compared with the TSR test. Also, the sensitivity of the AFV test to quantify the effect of thixotropic aging due to storage and temperature are discussed. The results show that the AFV technique can successfully quantify moisture damage and the effect of aging and temperature change.}, number={3}, journal={INTERNATIONAL JOURNAL OF PAVEMENT ENGINEERING}, author={Rashetnia, Reza and Kusam, Abhilash and Yadav, Shivpal and Pour-Ghaz, Mohammad and Tayebali, Akhtarhusein}, year={2022}, month={Feb}, pages={523–535} }